1. Technical Field
Example embodiments of the present invention relate to a mobile communication technology, and more specifically to a method for scheduling control information for data transmission in a mobile communication system, and a method for receiving the scheduled control information.
2. Related Art
Standardization on a mobile communication system such as A 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) and LTE-Advanced is going on in order to enable transmission of various data such as video, wireless data, etc. with a high data rate equal to that of a wired communication network.
In the LTE or LTE-Advanced system, time-frequency resources may be separated into a control region to which control channels such as Physical Downlink Control Channel (PDCCH) are allocated and a data region to which data channels such as Physical Downlink Shared Channel (PDSCH) are allocated. Downlink data may be transmitted from a base station to a terminal through the data region excluding the control region.
Also, in the LTE or LTE-Advanced system, the terminal identifies whether the base station transmits downlink data for it and whether the base station allocates resources for uplink data transmission to it, by performing blind decoding on the control region (that is, searching for the PDCCH corresponding to it in the control region) for each transmission time interval (TTI). According to the current LTE standard specification, the maximum number of blind PDCCH decoding, which can be performed by a terminal, is defined as 44.
Currently, a base station transmits control information for only a TTI in which the control information is transmitted. For example, control information for a first TTI is transmitted in the first TTI, and control information for a second TTI is transmitted in the second TTI. Therefore, the terminal should perform blind decoding for every TTIs to search for control information corresponding to it even when there is no control information corresponding to it or control information is not changed from the previously received one. This causes more power consumption of a battery-powered terminal.
Also, as described above, since a base station transmit control information for every TTIs, the number of OFDM symbols for PDCCH transmission becomes larger, and then resource regions for data transmission decreases so that overall capacity of a system decreases.